<template>
 <div>
   <h2>这是子组件</h2>
   <h4>{{value}}</h4>
   <button @click='changes'>修改</button>
 </div>
</template>

<script>
 export default {
   name: 'MySon',
   props: {
    value:{
        type:String,
        required:true
    }
   },
   methods:{
    changes(){
        this.$emit('input','abcd')
    }
   }
  
 }
</script>

<style scoped lang='less'>

</style>